The invention is directed to a fiber optic connector device. More particularly, the invention is directed to a fiber optic connector device that optically connects together electronic modules.
The xe2x80x9cneed for speedxe2x80x9d in today""s electronic world continues to drive the evolution of microprocessors and systems that support them. With each new generation of microprocessors, the promise of increased throughput can only be realized if the slowest link in the support system can be improved. Without opening the bottlenecks, the increased speed of a new microprocessor will be effectively slowed to the pace of the bottleneck system component. Thus, the new high speed microprocessor is typically left idling non-productively while waiting for the support systems to perform.
Most microprocessor devices, both for computation and for communication, operate based on the flow of electrons and the transmission of electromagnetic fields with wavelengths typically longer than one centimeter. The speed at which a signal can be successfully transmitted in these devices is typically inversely proportional to the distance over which the information needs to travel.
To overcome this problem of decreased speed at longer distances, these electronic devices have been adapted to communicate optically through photons and electromagnetic fields with wavelengths typically shorter than two micrometers. Optical signals traveling in optical waveguides still suffer from degradation over long distances but they are several orders of magnitude better than electrical signals. While these systems still process electrical signals, they are dependent upon optics to communicate over large distances. In this sense, the connectivity between processing nodes is optical.
In electronic devices, the speed bottlenecks typically occur in printed circuit boards and electrical connectors. The transmission line structures created within these components have a finite bandwidth, limiting the ability of the innerconnect to faithfully reproduce the original signal at the signal destination. Parasitic effects distort the signals, requiring a settling time before the transmission line can be sampled. Additionally, these electrical signals are susceptible to electromagnetic interference and data can be corrupted due to unwanted electrical interference.
Even though efforts are underway for creating higher bandwidth electrical interconnect solutions, the current bandwidth is typically less than two GHz depending on the desired transmission line characteristics. Using optics, the interconnect system does not represent the system bottleneck. In fact, optical systems have bandwidths in excess of 100 GHz which is well beyond the optical-electrical transducer capacity that is available today. Potentially, optical bandwidths could be high as 100,000 GHz.
Even though electrical interconnect systems have such limitations, many users are more comfortable with the proven performance of electrical interconnections over optical interconnections, particularly in harsh environments such as for use in military operations. Also, in military operations, size and weight of system components are critical. It is preferred that the size and weight be kept at a minimum because availability of space and carrying capacity, for example, on aircraft and submarines, are paramount. In FIG. 1, electronic modules M1-M6 are organized in a side by side fashion and secured in a rack 2. Each of the electronic modules M1-M6 includes a plurality of optical receptacles 4 that receive terminations 6. Selected pairs of the terminations 6 are interconnected by individual ones of optical cable 8.
In order to effectively make an optical connection between selected pairs of electronic modules M1-M6, it is imperative that the optical cable bends about a radius that is larger than the minimum bend radius rmin of the optical fibers contained within the optical cable 8. For example, in a worst case scenario, connecting position M1A with position M2A is illustrated in FIG. 2. A distance xe2x80x9cdxe2x80x9d is determined between center points of the positions M1A and M2A which usually represents a width of the module. To effectively optically connect electronic modules M1 and M2 at positions M1A and M2A, the optical cable 8, at a minimum, forms a semicircular loop having an inner radius ri that is at least equal to or greater than one half times the distance d. If the optical cable 8 is bent about a radius less than the minimiun bend radius rmin, the optical signal either degrades or it becomes corrupted rendering the optical signal unreliable.
Assume, for purposes of example, that the minimum bend radius Rmin of the optical cable 8 is 0.5 inches. Further, assume that the distance d is 1.0 inch. Applying the formula that the minimum bend radius rmin is greater than or equal to one half of the distance d, the result is 0.5 inches which is greater than or equal to 0.5 inches. Thus, the optical cable 8 having an inner radius 0.5 inches will transmit a reliable optical signal between the electronic modules.
However, assume also for example, that the electronic modules are narrower and, thus, the distance d is smaller. Assume that the distance d is 0.8 inches. If the minimum bend radius rmin is 0.5 inches and one half of the distance d is 0.4 inches, the optical interconnection between positions M1A and M2A shown in FIG. 2 will not yield a reliable optical signal because the minimum bend radius rmin 0.5 inches is greater than the inner radius ri, 0.4 inches of the optical cable 8. In short, narrowing the electronic modules M1-M6 will require new ways for making the optical interconnections therebetween.
Additionally, as the electronic modules M1-M6 become more compact with miniaturized electrical circuits, more optical receptacles may be added. Thus, the interconnection of the multiple optical receptacles becomes more complex. As shown in FIG. 1, several of the optical cables 8 are shown crisscrossing each other. As more and more optical receptacles 4 are added to the electronic modules, a xe2x80x9cbird""s nestxe2x80x9d arrangement of the optical cables is created. As a result, complexity of optically connecting and disconnecting the electronic modules becomes complex. Such complexities defeats the purpose of having individual electronic modules contained within the rack 2. A modular design should afford quick and simple replacement of any of the electronic modules. A xe2x80x9cbird""s nestxe2x80x9d arrangement of the optical cables 8 thwarts the goal of modular design.
It is an object of the invention to provide a single fiber optic connector device for optically connecting a plurality of racked electronic modules.
It is another object of the invention to provide a single fiber optic connector device that can be easily installed onto a plurality of electronic modules without creating a xe2x80x9cbird""s nestxe2x80x9d effect.
Another object of the invention is to provide a single fiber optic connector device that can be used with electronic modules without consideration of the width of any of the modules.
Yet another object of the invention is to provide a single fiber optic connector device that can be easily removed from a plurality of electronic modules and easily replaced without reference to an installation manual designating the appropriate optical receptacles for the appropriate terminations.
Accordingly, a fiber optic connector of the invention is described. One embodiment of the fiber optic connector of the invention transmits light and includes a body member and at least one strand of optical transmitting material. The body member is formed in a generally U-shaped configuration to define a first linear segment, a second linear segment and a looped segment interconnecting the first and second linear segments. The first and second linear segments extend generally parallel with one another and are disposed apart from one another at a spaced distance. The at least one strand of the optical transmitting material is carried by the body member to conform to the general U-shaped configuration and has a minimum bend radius for transmitting light around the looped segment. The looped segment has an inner radius of curvature greater than one half of the spaced distance and is at least equal to or greater than the minimum bend radius.
Another embodiment of the fiber optic connector of the invention includes an elongated fiber optic ribbon fabric that carries a plurality of fiber optic strands of optical transmitting material with each fiber optic strand having a minimum bend radius. The fiber optic ribbon fabric forms a serpentine configuration to define an array of linear segments and a plurality of looped segments. The array of linear segments is disposed in a generally parallel, sequential relationship at a spaced distance between sequential ones of the linear segments. A respective one of the looped segments interconnects the sequential ones of the array of linear segments. Each linear segment has at least one leg extending from a lateral edge of the fiber optic ribbon fabric. Each looped segment has an inner radius of curvature greater than one half of the spaced distance and at least equal to or greater than the minimum bend radius so that light can be transmitted from one leg to another leg through the fiber optic ribbon fabric.
Another embodiment of the invention is the fiber optic connector that selectively and optically connects together a plurality of modules arranged in a juxtaposed relationship. Each module has at least one optical receptacle formed therein. The fiber optic connector of the invention includes an elongated fiber optic ribbon fabric as described above. Each linear segment has at least one leg extending from a common lateral edge of the fiber optic ribbon fabric and is positioned along the common lateral edge to align with and engage the optical receptacles in each of the modules to optically connect together the plurality of modules thereby causing sequential ones of the array of linear segments to be disposed apart from one another at a spaced distance. Each looped segment has an inner radius of curvature as described above so that light maybe transmitted from one module to another.